photochemical smog

American  

noun

Meteorology.

1. air pollution containing ozone and other reactive chemical compounds formed by the action of sunlight on nitrogen oxides and hydrocarbons, especially those in automobile exhaust.

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Etymology

Origin of photochemical smog

First recorded in 1957; photo- + chemical

Example Sentences

Not the good, high-altitude ozone that shields us from dangerous UV light, but bad ozone, hovering right above ground level — stinking, brownish, grayish photochemical smog.

From Los Angeles Times • Mar. 26, 2026

Cleaner cars have wrought wonders in getting rid of photochemical smog, when all we need to do is buy one.

From Los Angeles Times • Mar. 26, 2026

It was a Caltech professor, Arie Jan Haagen-Smit, not GM engineers or chemists, who proved in the 1950s the connection between motor vehicles and the lethal photochemical smog over the cities and suburbs of California.

From Scientific American • May 9, 2019

This ozone is a toxic component of photochemical smog.

From Textbooks • Feb. 14, 2019

Ozone, a principal component of photochemical smog, discolors and disintegrates clothing and causes rubber to become brittle and crack.

From Time Magazine Archive